clutter meaning, definition, what is clutter: to cover or fill a space or room with to...: Learn more. CLUTTER meaning: 1. (a lot of objects in) a state of being untidy: 2. to fill something in an untidy or badly…. Learn more. Clutter definition: to fill or litter with things in a disorderly manner.. See examples of CLUTTER used in a sentence. The meaning of CLUTTER is to run in disorder. How to use clutter in a sentence.